Rotary buffing sleeve

ABSTRACT

A reciprocable sander having a support shaft and a rotatable sleeve positioned in spaced relation about the shaft. The shaft and rotatable sleeve are interconnected and piston means are provided within the sleeve in operative engagement with the sleeve. On actuation of the piston means, a reciprocating movement is produced in the sleeve and means are also provided to transmit rotational movement to the sleeve. Sanding means are carried by the sleeve with the rotational and reciprocatory movement of the sleeve being, thereby, transmitted to the sanding means.

United States Patent [1 1 Burns Mar. 4, 1975 ROTARY BUFFING SLEEVE 3,528,197 9/1970 Wallace 51/34 R [75] Inventor: Russell W. Burns, Ventura, Calif.

Primary Exammer-Al Lawrence Smith [73] Assignee: Merit Abrasive Products, Inc., Assistant E Ramsey Compton, Cahf- Attorney, Agent, or Firm-Ellsworth R. Roston [22] Filed: June 4, 1973 21 Appl. No.: 366,318 [571 ABSTRACT A reciprocable sander having a support shaft and a rotatable sleeve positioned in spaced relation about the g i jgg shaft. The shaft and rotatable sleeve are intercon- [58] Fieldof Search 51/34 R, 34 J, 49, 254; and means are P the 74/840. 64/23 7 sleeve in operative engagement with the sleeve. On actuation of the piston means, a reciprocating movement [56] References Cited is produced in the sleeve and means are also provided to transmit rotational movement to the sleeve. Sand- UNITED STATES PATENTS ing means are carried by the sleeve with the rotational 63,l65 3/1867 Ladd et al 51/34 R and recipro atory movement of the sleeve being, 678,961 LlllIOn X thereby transmitted to the anding means 2,905,008 9/1959 Sears 3,312,118 4/1967 Aubert 51/34 R X 6 Claims, 7 Drawing Figures V 4 I I, 1M aywwww I! A I t W 17 PATENIEBHAR 4% 3,868,791 Sam 1 g l ROTARY BUFFING SLEEVE BACKGROUND OF THE INVENTION ln forming metal sheet material, an oxide coating may be formed on the surface of the metal which is transferred to forming rolls that contact the surface of the moving strip of metal. For example, in the hot rolling of aluminum, a coating of aliminum oxide forms on the metal strip and is transferred to the surfaces of the forming rolls. This transfer of metal oxide changes the surface configuration of the forming rolls which is undesiraalbe. Thus, it is conventional practice to remove the metal oxide from the forming rolls or from the surface of the metal strip itself through use of an oscillating rotary sander.

The abrasive grits which contact the surface of a mill roll during sanding of the roll are not entirely uniform in their size and configuration. Thus, if the sander were merely rotated, but not oscillated, the grits would cause uneven wear of the roll surface. It is for this reason that sanders for sanding the surface of a mill roll are commonly reciprocated to produce uniform sanding of the roll.

Sanders presently in use are relatively bulky and are reciprocated through a mechanical linkage such as a crank which interconnects the sander with an eccentric. The mechanical linkage used to reciprocate the sander has the effect of lengthening the sander.

The bulky size and excessive length of present sanders make them difficult to use in installations where space is limited. Frequently, the space available for installation of a sander in a rolling mill is quite limited. Metal rolling equipment is massive and requires special supports, special foundations, etc. Due to the space demands of the metal rolling equipment, the space which is left for installation of sanders is frequently quite limited. Present sanders are, thereby, difficult to install because their bulky size and excessive length may not fit and space which is left in the rolling mill for their installation.

In view of the above difficulties, it would be desirable to have a reciprocatory rotary sander having a relatively compact size and a shortened length. Such a sander would be more versatile and could be more readily installed in a rolling mill in locations which will not accept present sanders having a mechanical drive to produce reciprocation.

SUMMARY OF THE INVENTION In accord with the present invention, I have provided a reciprocable sander having a support shaft and a rotatable sleeve positioned about the shaft and in spaced relation thereto. The sleeve and the support shaft are interconnected and piston means are provided within the sleeve and in operative engagement with the sleeve. Actuation of the piston means produces reciprocatory movement of the sleeve while means are provided to transmit rotational movement to the sleeve and to sanding means carried by the sleeve.

The rotational and reciprocatory movement of the sleeve, thus, provides a corresponding rotational and reciprocatory movement of the sanding means. Inasmuch as the piston means is positioned within the rotatable sleeve, the sander is relatively compact in size and is shorter than present sanders of equivalent size which use a mechanical drive reciprocation of the sander.

Thus, the present sander is more versatile than previous sanders.

The present sander may include a support shaft which is stationary with the sleeve being rotated and reciprocated with respect to the stationary shaft. The piston means may include an air piston having an annular configuration with the air piston being positioned between the support shaft and the rotatable sleeve. Air passages defined within the shaft may be utilized to supply air to the air piston for reciprocation of the sleeve.

In supporting the sleeve, a rotatable support bearing may be positioned on the shaft with the external surface of the bearing in sliding engagement with the sleeve. Preferably, the rotational movement of the bearing and the sleeve is synchronized with means interconnecting the bearing and sleeve to provide the synchronous rotational movement while permitting sliding axial movement of the bearing and sleeve.

In synchronizing the rotational movement of the bearing and sleeve, an axially positioned slot may be provided in the sleeve in overlying relation to an axially positioned groove in the bearing. A ball may be retained in the slot with the ball extending into the groove. The sleeve and bearing may, thus, be interconnected through the ball for synchronous rotational movement. Preferably, the sleeve is formed of a hard strong metal with the bearing being formed of a softer metal to reduce sliding friction between the sleeve and the bearing.

The air piston employed in the sander may have an annular configuration with the air piston being positioned between the shaft and sleeve and in fixed axial engagement with the shaft. An inner cylinder bell having annular configuration may then be positioned inwardly from the air piston in slidable engagement with the shaft and in fixed axial engagement with the sleeve. An outer cylinder bell having an annular configuration may be positioned outwardly from the air piston in slidable engagement with the shaft and in fixed engagement with the sleeve. The inner and outer cylinder bells may then be joined by a cylinder positioned within the sleeve with the cylinder having an inner surface in sliding engagement with the air piston.

Air passages may then be provided to introduce or withdraw air from the region bounded by the inner cyl' inder bell, the air piston and cylinder or the region bounded by the outer cylinder bell, the air piston and the cylinder. Air may be introduced into the region between the inner cylinder bell and the air piston to pro vide movement of the inner cylinder bell away from the piston. Likewise, air may be introduced into the region between the outer cylinder bell and the air piston to move the outer cylinder bell away from the air piston. The fixed axial connection of the inner and outer cylinder bells to the rotatable sleeve, thereby produces movement of the sleeve in response to movement of the cylinder bells.

A first air opening may be provided in the shaft which is positioned inwardly adjacent the air piston with a second air opening in the shaft positioned outwardly adjacent the air piston. An outer face on the inner cylinder bell may then be provided with an annular groove which is positioned in overlying relation to the first air opening when the inner cylinder bell is moved to a position adjacent to the fixed air piston.

An annular groove may also be provided in the inner face of the outer cylinder bell with the annular groove overlying the second air opening on movement of the outer cylinder bell to a position adjacent the fixed air piston. The annular grooves in the inner and outer cylinder bells, thereby, prevent blockage of the air passages by the cylinder bells.

The sander of the present invention may be rotated through means positioned either internally or externally of the sander. Thus, for example, the sander may be rotated externally through a chain drive to impart rotational movement to the sander sleeve through a drive sprocket. Also, the sander may be rotated through motor means positioned within the rotatable sleeve. The internally positioned motor means may be drivingly engaged with the sander sleeve through any convenient means such as a gear train in which a driven pinion gear is interconnected with a ring gear affixed to the sander sleeve.

DESCRIPTION OF THE DRAWINGS In the drawings, which are merely illustrative of an embodiment of the invention,

FIG. 1 is a perspective view illustrating a strip of aluminum being drawn between forming rolls with a reciprocable sander positioned adjacent each forming roll for removing metal oxide from the roll;

FIG. 2 is a sectional view along the line 2-2 of FIG. 1 illustrating one end of the sander with the valving mechanism for reciprocation of the sander;

FIG. 3 is an enlarged side sectional view, similar to FIG. 2, illustrating in greater detail the valving mechanism for reciprocation of the sander;

FIG. 4 is a sectional view taken along the line 4-4 of FIG. 3 illustrating the interconnection between a support sleeve and a bearing sleeve to provide synchronous rotational movement while permitting axial movement between the support sleeve and the bearing sleeve;

FIG. 5 is a side sectional view taken along the line 5-5 of FIG. 1 illustrating an end portion of the sander which includes a rotational drive mechanism for the sander;

FIG. 6 is an end sectional view taken along the line 6-6 of FIG. 5 illustrating the interconnection between a drive sprocket for the sander and a support sleeve rotated by the drive sprocket, and

FIG. 7 is a side sectional view of an embodiment of the sander in which the sander is rotated by a drive motor positioned within the sander interior.

DETAILED DESCRIPTION As illustrated in FIG. 1, an aluminum strip 2 may be formed by passing the strip between forming rolls 4 which contact the strip and are supported by back-up rolls 6. With the aluminum strip 2 at an elevated temperature, there will be a coating of aluminum oxide on the strip which will be transferred to the surfaces of the forming rolls. This transfer will change the surface configuration of the forming rolls 4 which is undesirable. Thus, the metal oxide is continuously removed from the rolls 4 by oscillating rotary sanders denoted generally as 8. The sanders 8 may be driven through a chain drive 10 with the sanders continuously oscillating and rotating against the rolls 4 to remove metal oxide.

The abrasive grits which contact the surfaces of the rolls 4 are not entirely uniform in their size and configuration. Thus, if the sanders 8 were rotated but not oscillated, the grits would cause uneven wear of the roll surfaces. For example, a large abrasive grit continuously contacting an area on the surface of the roll 4 would produce more wear than a smaller abrasive grit striking another area of the surface. For this reason, it is common practice to reciprocate a sander, such as the sanders 8, to produce uniform sanding of a forming roll.

The machinery used in rolling metal strip, whether 7 steel or non-ferrous strip, is massive. Thus, metal rolling equipment may require special supports, special pits positioned beneath the rolls, etc. The positioning of metal rolling equipment may also vary from one installation to another depending on the space limitations of the building structure which houses the equipment.

Due to the many variations encountered in the rolling mill installations, it is frequently very difficult to find space for a sander adjacent to a mill roll or adjacent to the metal strip, i.e., for example, where the sander contacts a moving hot steel strip to remove an oxide coating from the metal. The problems in locating reciprocatory sanders within the available space in a rolling mill are particularly acute where the sander mechanism is bulky.

Previous sanders have been reciprocated by a mechanical linkage such as a crank interconnecting the sander with an eccentric and are quite bulky. The use of a crank and an eccentric to provide reciprocation also has the effect of lengthening the sander. This may make it impossible to use the sander in locations where the overall length of the sander is an important consideration, such as in the space between support stanchions for a mill roll, etc.

The rotary and reciprocatory sander of the invention referred to as 8 in FIG. 1 is relatively compact in size and particularly in length. The compactness of the sander 8 is a direct result of the mechanism employed for its reciprocation, as will be described, positioned within the interior of the sander. I

FIG. 2 is a side sectional view taken along the line 2-2 of FIG. 1 and illustrates an end portion 8a of the sander which contains the internal mechanism for reciprocating the sander. The end portion 8a is supported by a stationary stub shaft 12 that is fixedly positioned on a support base 13. The base 13 includes an upright member 15 having an aperture 17 therein. The aperture l7 surrounds the stub shaft 12 with the shaft retained in the aperture by any convenient means such as a locking screw 19. The screw 19 threadedly engages an opening in the upright member 15 and projects into a depression in the stub shaft 12.

A bearing sleeve 14 may be rotatably positioned with respect to the stub shaft 12 by tapered rolling bearings 16 and 18. The bearings 16 and 18 are positioned in opposed relation to resist axial movement of the sleeve 14 in either direction while permitting rotational movement of the sleeve.

Positioned outwardly of the bearing sleeve 14 is a support sleeve 20 whose inner surface engages the outer surface of the bearing sleeve. The support sleeve 20 is preferably formed from a relatively hard, strong metal such as steel while the support sleeve 14 is preferably formed of a softer metal such as brass to reduce the frictional contact between the bearing sleeve and support sleeve.

A sander drum 22 having a plurality of axial slots 23 spaced about its circumference is positioned outwardly from the support sleeve 20. Abrasive packs 24 are car ried within the axial slots 23 to provide a plurality of the abrasive packs which extend radially from the surface of the drum 22. As will be described, the position of the drum 22 is fixed with respect to the support sleeve 20. Thus, rotational and reciprocatory motion of the sleeve 20 produces a corresponding movement of the drum 22 and the abrasive packs 24.

The support sleeve 20 is also supported by radial thrust bearings 26 and 28. The outer race of the radial thrust bearing 26 engages the inner surface of the support sleeve 20 while the inner race of the bearing 26 is supported by an inner cylinder bell 30 having a hub 31 which engages the inner race of the bearing.

The outer race of the bearing 28 engages the inner surface of the support sleeve 20 with the inner race of bearing 28 being supported by an outer cylinder bell 32 having a hub 33 engaging the inner race. The inner cylinder bell 30 and outer cylinder bell 32 are interconnected by a cylinder 34 with an air piston 36 fixedly positioned on the shaft 12 between the outer and inner cylinder bells and the outer circumferential surface of the piston 36 in sliding engagement with the inner surface of the cylinder 34.

A seal retainer 37 is positioned outwardly from the outer cylinder bell 32 with a retainer ring 39 positioned in overlying relation to the seal retainer. The retainer ring 39 maintains the seal retainer 37, bearing 28, outer cylinder bell 32, cylinder 34, bearing 26, and inner cylinder bell 30 in a fixed relation with respect to the sup port sleeve 20.

An air cavity 38 is defined in the region bounded by the cylinder 34, the outer face of the inner cylinder bell 30 and the fixed piston 36 while an air cavity 40 is defined by the cylinder 34, the inner face of the outer cylinder bell 32 and the air piston 36. An air passage 42 within stub shaft 12 leads to the air cavity 38 while an air passage 44 leads to the cavity 40. When air is introduced through air passage 42, the air cavity 38 expands in volume by movement ofthe inner cylinder bell 30 away from the fixed air piston 36. This causes the support sleeve 20 and drum 22 to move to the right from their position shown in FIG. 2. At the same time, the outer cylinder bell 32 and the cylinder 34 undergo movement to the right which reduces the volume of cavity 40 with air therein being exhausted through air passage 44.

When air is introduced through air passage 44, the cavity 40 expands in volume by movement of the outer cylinder bell 32 to the left from its position shown in FIG. 2. This causes a leftward movement of support sleeve 20, drum 22, inner cylinder bell 30 and cylinder 34. An air cavity 40 expands in volume, there is a corresponding reduction in volume in the cavity 38 with exhaust of air through air passage 42.

A stationary air manifold 46 positioned about the stub shaft 12 communicates with the air passages 42 and 44. Air is introduced into or exhausted from the manifold 46 through air conduits 48 and 50. The control of air flow through the conduits 48 and 50 may be controlled by a conventional four-way valve 52. As air is introduced through air conduit 48 to air passage 44, air is exhausted through air passage 42 and air conduit 50. Conversely, when air is introduced through air conduit 50 and air passage 42, air is exhausted through air passage 44 and conduit 48.

A lubrication passage 54 may be positioned within stub shaft 12 to permit introduction of a lubricating oil to the interior of the sander. In forming the air passages 42 and 44 and the lubrication passage 54, the end of the stub shaft 12 may be drilled to provide axial bores with side bores then being drilled through the shaft to connect with the axial bores. The openings ramaining in the end of the stub shaft 12 from this machining operation may be closed in any convenient manner, such as by screw caps 56 which threadedly engage the openings.

The tapered rolling bearings 16 and 18, together with the bearing sleeve 14 may be held by lock nut 58 which engages threads 60 on the inner end of stub shaft 12. By tightening the lock nut 58 against a washer 62 positioned between the lock nut and the inner race of bearing 18, the bearings 16 and 18 and the bearing sleeve 14 may be fixed in their axial positions with respect to stub shaft 12.

FIG. 3 is an enlarged sectional view of the sander mechanism shown in FIG. 2 and illustrates the reciprocation mechanism in greater detail. As described, the air piston 36 is fixed to the stub shaft 12. This may be accomplished by snap rings 64 which engage circumferential grooves 65 in the stub shaft 12. With the rings 64 retained by the grooves 65, the rings bear on either side of the air piston 36 to fix its position on the shaft 12.

The inner race of the tapered roller bearing 16 engages a step 66 on shaft 12. The engagement of the roller bearing 16 with step 66 and the engagement of lock nut 58 with roller bearing 18, forces the bearings 16 and 18 against support sleeve 14 which acts as a strut between the bearings. The position of the bearings 16 and 18 and the bearing sleeve 14 are, thus, fixed axially with respect to the stub shaft 12.

As described, both bearing sleeve 14 and support sleeve 20 are rotatable while support sleeve 20 is reciprocated with respect to the bearing sleeve 14. To reduce wear at the interface between support sleeve 20 and bearing sleeve 14, the rotational movement of the support sleeve and bearing sleeve may be synchronized. To accomplish this, an axial slot is provided in support sleeve 20 with a corresponding axial groove 68 provided in bearing sleeve 14. A plurality of balls 72 formed of a hard resilient material such as steel are positioned within the slot 70 and groove 68. The balls 72 may be held in a spaced-apart relation by a retainer 74. The retainer 74 has a plurality of openings 75 and each of the balls 72 is confined within an opening 75 in a spaced-apart relation.

The balls 72 are free to roll within slot 70 and groove 68 on reciprocatory movement of support sleeve 20 with respect to bearing sleeve 14. However, the balls 72 fix the rotational position of the support sleeve 20 and bearing sleeve 14. The rotational movement of the support sleeve 20 is, thus, synchronized with the rotational movement of the bearing sleeve 14.

As illustrated in FIG. 3, support sleeve 20 and drum 22 have undergone movement in the direction of the arrow A from their position shown in FIG. 2. Also, the outer bell cylinder 32 has moved away from fixed air piston 36 by the introduction of air through the air passage 44 into cavity 40. Concurrently, the inner bell cylinder 30 has moved in the direction of arrow A with the outer face of the inner bell cylinder abutting the face of fixed piston 36 with air exhausted through air passage 42. With the movement of the inner bell cylinder 30 in the direction of arrow A, an annular groove 76 in the inner bell cylinder is positioned over the air passage 42. This prevents obstruction of the air passage by the inner bell cylinder 30. This permits introduction of air through air passage 42 to the region between inner bell cylinder 30 and piston 36 during the stroke of the sander and support sleeve in the direction of the arrow B.

An annular groove 78 in the inner surface of outer bell cylinder 32 is positioned over the air passage 44 after translation of the sander in the direction of arrow B. This prevents obstruction of the air passage 44 by the outer cylinder bell 32 and permits air to be introduced between the outer bell cylinder 32 and piston 36 in causing movement of the sander in the direction of the arrow A. The air passage 44 leads through the stationary manifold 46 to a port 82 while the air passage 42 leads through the manifold to a'port 80.

A number of seals are provided to prevent the leakage of air in the operation of the reciprocation mechanism for the sander. A seal 84 is provided between the inner bell cylinder and the surface of the stub shaft 12 to prevent the leakage of air between the contacting surfaces of the stub shaft and the bell cylinder 30. Also, a seal 86 is provided between the outer surface of the bell cylinder 30 and the inner surface of the cylinder 34 to prevent air leakage between these surfaces.

Seals 88 may be positioned between the inner surface of the piston 36 and the contacting surface of the stub shaft 12 while seals 90 may be positioned between the exterior surface of the piston and the inner surface of the cylinder 34. A seal 92 prevents air leakage between the inner surface of the outer bell cylinder 32 and the stub shaft 12 while a seal 94 prevents air leakage between the outer surface of the bell cylinder and the inner surface of the cylinder 34.

A seal 96 is positioned between the seal retainer 37 and the support sleeve 20 while a slipper seal 98 is provided between the seal retainer and the stub shaft 12. The end retainer ring 39, as described previously, partially overlies the seal retainer 37 with the retainer ring being secured to the sander drum 22 through any con venient means such as screws 100 which extend through apertures in the retainer ring to engage threaded openings in the sander drum.

The port 82 communicates with air passage 44 through an annular passage 102 in the manifold 46. Similarly, the port 80 communicates with air passage 42 through an annular passage 104. A plurality of seals 106 are positioned between the stub shaft 12 and the contacting surfaces of the air manifold 46 to prevent air leakage from the annular passages 102 and 104 along the outer surface of the stub shaft 12.

As illustrated in FIG. 3, the support sleeve 20, sanding drum 22, bearing sleeve 14, and seal retainer 37 are rotated during usage of the sander. The inner bell cylinder 30, cylinder 34, and outer bell cylinder 32 undergo reciprocatory movement which is transferred to the support sleeve 20 through the thrust bearings 26 and 28. The inner and outer bell cylinders 30 and 32 and the cylinder 34 may undergo some rotational movement due to frictional forces transmitted from the rotating support sleeve 20 through the bearings 26 and 28. However, any rotational movement of the inner and outer bell cylinders 30 and 32 is minimal as compared with the rotation of the support sleeve 20 since there is no rotational driving force transmitted directly to the inner and outer bell cylinders. The air piston 36, as described previously, is fixed to the stationary stub shaft 12 and does not move at all.

FIG. 4 is a sectional view along the line 4--4 of FIG. 3 and illustrates the interconnection between the support sleeve 20 and bearing sleeve 14. The axial slot 70 in support sleeve 20 is positioned over a corresponding axial groove 68 in the bearing sleeve 14. The balls 72, thereby, extend into both the slot 70 and groove 68 to interconnect the support sleeve 20 and bearing sleeve 14. The balls 72 maintain the support sleeve 20 and bearing sleeve 14 fixed with respect to rotational movement but permit axial movement of the support sleeve and bearing sleeve 14.

FIG. 5 is a sectional view along the line 5--5 of FIG. 1 of an end portion 8b of the sander with a drive mechanism for imparting rotational movement to the sander. As illustrated, the end portion 8b is oppositely positioned to the end portion 8a, (shown in FIGS. 2 and 3) which contains the valving mechanism for reciprocation of the sander.

The end portion 8b is supported by a stub shaft 108 which may be secured to support base 13 by a lock screw 138. Mounted on the stub shaft 108 are tapered roller bearings 110 and 112 which support a bushing sleeve 114. The bushing sleeve contains an axial groove 116 in alignment with an axial slot 118 in the support sleeve 20. A plurality of balls 120 within the slot 118 and groove 116 fix the rotational positions of the support sleeve 20 and bearing sleeve 114, but permit axial movement of sleeve 20 with respect 'to the bearing sleeve 114. The balls 120 may be held in a spaced-apart relation by a retainer 122.

The inner race of the bearing 112 is positioned against a step 124 in the stub shaft 108 while a lock nut 148 engages threads 146 on the inner end of the stub shaft. As the lock nut 148 is tightened on the threads 146, it compresses a washer 150 against the bearing 110. The position of the bearings 110 and 112 and the bushing sleeve 114 is, thereby, fixed axially with respect to the stub shaft 108.

A drive seal ring 126 is positioned against the outer ends of the support sleeve 20 and sander drum 22. A drive sprocket 128 having teeth 130 is secured to the outer surface of the drive seal ring 126 by screws 136 in threaded engagement with apertures in the end of the sander drum 22. Dowel pins 32 fixedly secured to the drive sprocket 128 project inwardly into pin slots 134 in the support sleeve 20. On rotation of the drive sprocket 128, the rotational movement is transmitted to the support sleeve 20 through the dowel pins 132.

A lubrication passage 140 may be provided within the interior of the stub shaft 108 with the end extension of the passage being conveniently closed by a cap 141. Oil slipper seals 142 may be provided between the fixed shaft 108 and the drive seal ring 126 which rotates with the support sleeve 20, sanding drum 22, and drive sprocket 128. Also, a seal 144 may be provided between the outer surface of seal ring 126 and the inner surface of support sleeve 20.

FIG. 6, which is a sectional view along line 66 of FIG. 5, illustrates the manner in which the dowel pins 132 are received within pin slots 134 in the support sleeve 20. As shown, a plurality of dowel pins 132 are positioned circumferentially about the drive sprocket 128 with each dowel pin engaging one of a plurality of circumferentially spaced pin slots 134. Engagement of the dowel pins 132 with pin slots 134 transmits rotational movement to the support sleeve 20.

The abrasive packs 24 extend radially outwardly from the sanding drum 22. Each of the packs 24, shown at the top of FIG. 5, includes a T-shaped foot 152 which engages one of the slots 23 of the same configu' ration in the drum 22. The packs 24may include a number of sheets 154 of paper or cloth that is coated with abrasive material. The individual sheets 154 may be joined to the foot 152 by any convenient means such as stitching through the sheets and foot at a connection point indicated as 156.

An alternate embodiment of the invention is illustrated in FIG. 7 in which the sander is powered by a motor 158 positioned within the support sleeve 20. The motor 158 may be connected to the inner end of the fixed stub shaft 108 with the motor being powered through fluid conduits 160. An output shaft 162 may, thereby. provide rotational movement to a pinion gear 164 which is connected to a ring gear 166 affixed to the interior of support sleeve 20.

As described, the sander of the invention may be supported at its end by stub'shafts which support the rotatable support sleeve that runs the length of the sandner. Unlike previous sanders, the sander of the invention is quite compact in sizewith the mechanism for reciprocation of the sander being contained within the sander interior. This permits the sander to be used in locations where space requirements are quite limited. Thus, the sander is more versatile than previous sanders whose bulky size and configuration limited their usage in installations where space was limited.

I claim:

1. A reciprocable sander comprising:

a support shaft;

a rotatable support sleeve positioned about the shaft and in spaced relation thereto;

means interconnecting the sleeve and shaft;

pistons means positioned within the sleeve in operative engagement with the rotatable support sleeve with actuation of the piston means producing a re ciprocating movement of the sleeve;

means to transmit rotational movement to the sleeve;

sanding means carried by said support sleeve;

said support shaft being stationary and said support sleeve being rotated and reciprocated with respect to said stationary shaft;

a rotatable support bearing positioned on said shaft,

and

said bearing having an external surface in sliding engagement with said sleeve. v

2. A reciprocable sander comprising:

a support shaft;

a rotatable support sleeve positioned about the shaft and in spaced relation thereto;

means interconnecting the sleeve and shaft;

piston means positioned within the sleeve in operative engagement with the rotatable sleeve with actuation of the piston means producing a reciprocating movement of the sleeve;

motor means positioned within said support sleeve for imparting rotational movement to said support sleeve, and

sanding means carried by said sleeve,

whereby rotational movement of the sleeve provides contact between the sanding means and a surface with the relative position of the sanding means and the surface being varied through the reciprocatory movement of the sleeve.

3. The sander of claim 1 including means interconnecting said bearing and said sleeve for synchronous rotational movement and relative sliding axial movement.

4. The sander of claim 3 including an axially positioned slot in said sleeve;

an axially positioned groove in said bearing;

said slot positioned in overlying relation to said groove; and

a ball retained in said slot and extending into said groove,

whereby the sleeve and bearings are interconnected through the ball for synchronous rotational movement.

5. The sander of claim 1 wherein the sleeve is formed of a hard strong metal and the bearing is formed of a softer material.

6. The sander of claim 1 including thrust bearings positioned between the shaft and rotatable support bearing, and

said thrust bearings being positioned to rotatably support the support bearing with respect to the shaft and to prevent axial movement of the support hearing with respect to the shaft. 

1. A reciprocable sander comprising: a support shaft; a rotatable support sleeve positioned about the shaft and in spaced relation thereto; means interconnecting the sleeve and shaft; pistons means positioned within the sleeve in operative engagement with the rotatable support sleeve with actuation of the piston means producing a reciprocating movement of the sleeve; means to transmit rotational movement to the sleeve; sanding means carried by said support sleeve; said support shaft being stationary and said support sleeve being rotated and reciprocated with respect to said stationary shaft; a rotatable support bearing positioned on said shaft, and said bearing having an external surface in sliding engagement with said sleeve.
 2. A reciprocable sander comprising: a support shaft; a rotatable support sleeve positioned about the shaft and in spaced relation thereto; means interconnecting the sleeve and shaft; piston means positioned within the sleeve in operative engagement with the rotatable sleeve with actuation of the piston means producing a reciprocating movement of the sleeve; motor means positioned within said support sleeve for imparting rotational movement to said support sleeve, and sanding means carried by said sleeve, whereby rotational movement of the sleeve provides contact between the sanding means and a surface with the relative position of the sanding means and the surface being varied through the reciprocatory movement of the sleeve.
 3. The sander of claim 1 including means interconnecting said bearing and said sleeve for synchronous rotational movement and relative sliding axial movement.
 4. The sander of claim 3 including an axially positioned slot in said sleeve; aN axially positioned groove in said bearing; said slot positioned in overlying relation to said groove; and a ball retained in said slot and extending into said groove, whereby the sleeve and bearings are interconnected through the ball for synchronous rotational movement.
 5. The sander of claim 1 wherein the sleeve is formed of a hard strong metal and the bearing is formed of a softer material.
 6. The sander of claim 1 including thrust bearings positioned between the shaft and rotatable support bearing, and said thrust bearings being positioned to rotatably support the support bearing with respect to the shaft and to prevent axial movement of the support bearing with respect to the shaft. 